MiR-574-5p mediates the cell cycle and apoptosis in thyroid cancer cells via Wnt/β-catenin signaling by repressing the expression of Quaking proteins

Thyroid cancer is the most frequently occurring type of endocrine tumor, with a rapidly increasing incidence rate. MicroRNA (miR)-574-5p is a candidate oncogene in various types of cancer. The present study identified that miR‑574‑5p affected the cell cycle distribution and apoptosis of BCPAP and FTC133 thyroid cancer cells via β‑catenin/Wnt signaling by targeting Quaking proteins (QKIs). An MTT assay demonstrated that the knockdown of miR‑574‑5p suppressed the proliferation of the thyroid cancer cells. Fluorescence‑activated cell sorting analysis demonstrated that the inhibition of miR‑574‑5p induced the G1/S phase arrest and apoptosis of the cells. Reverse transcription‑quantitative polymerase chain reaction and western blot analyses revealed that the knockdown of miR‑574‑5p significantly upregulated the mRNA and protein expression levels of QKIs. Furthermore, western blot analysis identified that the knockdown of miR‑574‑5p also repressed the Wnt/β‑catenin pathway via downregulating the expression of β‑catenin, cyclin D1 and survivin, and upregulating the phosphorylation of β‑catenin. The further depletion of QKIs in combination with the knockdown of miR‑574‑5p not only increased the expression of β‑catenin, cyclin D1 and survivin, but also rescued the apoptosis of thyroid cancer cells induced by the miR‑574‑5p knockdown. In conclusion, these findings indicated that the aberrant upregulation of miR‑574‑5p may be oncogenic, through regulating the Wnt/β‑catenin pathway by targeting QKIs.